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AMD Radeon HD 7970: Promising Performance, Paper-Launched

Radeon HD 7970: A Holiday Surprise That You Can't Buy

Leading into December, we didn’t really expect to see a next-generation graphics card in the 31 days before 2012. In fact, even mid-month, after we’d already been briefed, the plan was to launch in January. Windows 8 and its accompanying DirectX 11.1 API update aren’t expected for months still, and today’s high-end graphics cards are well-equipped to handle modern games. Despite the fact that AMD purportedly stopped production of its Radeon HD 6990 months ago, we were worried that rumors of poor 28 nm yields at TSMC meant there was no way a new GPU could be readied in time.

When AMD moved its launch date up to today, we were even more bowled over. The official line from AMD was that “After collecting feedback from our partners and evaluating our overall readiness…we believe this new date allows us to get ahead of the Christmas season rush and CES.” Getting ahead of the Christmas rush by launching 72 hours before the big day is a tough line to swallow, especially after a follow-up confirming that cards won't be shipping until January 9th. The unfortunate result is that a lot of AMD’s software partners were unprepared to provide us with the applications needed to properly test the GPU’s new features. So, this article officially goes down as a preview, rather than a review. We will, of course, follow up when all of the proper tools are available for testing.

Meet Radeon HD 7970

Regardless of whether or not it’s ready for the world, or the world is ready for it, AMD’s Radeon HD 7970 is up and running in the Tom’s Hardware lab. This card is no minor revision of the Radeon HD 6000 series. The company’s ”Southern Islands” architecture was re-designed from the ground up with a long list of new features and capabilities, including DirectX 11.1 compatibility. Composed of 4.31 billion transistors etched on a 28 nm process, the flagship Tahiti GPU sports about 160% of the Cayman design’s reported transistor count. However, adopting the latest lithography node allows AMD to cram that extra complexity into a 365 mm² die, which is smaller than its predecessor’s 389 mm² surface area.

Before we delve into the major architectural redesign, let’s have a closer look at the new card’s specifications compared to its competition.

Radeon HD 7970Radeon HD 6970Radeon HD 6990GeForce GTX 580
Stream processors204815363072512
Texture Units1289619264
Full Color ROPs32326448
Graphics (Shdr) Clock925 MHz880 MHz830 MHz772 (1544) MHz
Texture Fillrate118.4 Gtex/s84.5 Gtex/s159.4 Gtex/s49.4 Gtex/s
Memory Clock1375 MHz1375 MHz1250 MHz1002 MHz
Memory Bus384-bit256-bit2x 256-bit384-bit
Memory Bandwidth264 GB/s160 GB/s160 GB/s192.4 GB/s
Graphics RAM3 GB GDDR52 GB GDDR52 GB GDDR51.5-3 GB GDDR5
Die Size365 mm2389 mm22 x 389 mm2520 mm2
Transistors (Billion)4.312.645.283
Process Technology28 nm40 nm40 nm40 nm
Power Connectors1 x 8-pin, 1 x 6-pin1 x 8-pin, 1 x 6-pin2 x 8-pin1 x 8-pin, 1 x 6-pin
Maximum power (TDP)250 W250 W375 W244 W
Price$549 MSRP$340-$380 (Newegg)$700-$750 (EOL)$500-$530 (1.5 GB)$590-$730 (3 GB)

This product boasts notable advantages over the Radeon HD 6970, with 33% more stream processors and texture units, and a 65% net memory bandwidth increase thanks to its 384-bit memory bus. The only specifications that these cards share are 32 ROPs and a 250 W TDP. Based on those figures alone (and the fact that this is apparently going to be a $550 card), we’d expect the Radeon HD 7970 to decimate the 6970, edge past the GeForce GTX 580, and fall behind AMD’s Radeon HD 6990. There’s frankly a lot more to this story than gaming performance, though, and we’ll get to that in an in-depth exploration of AMD’s new Graphics Core Next architecture.

But first, we’ll share what we know about the Radeon HD 7000 series. Despite rumors to the contrary, all of the 28 nm Radeon 7000 series GPUs, previously code-named Southern Islands, are based on the Graphics Core Next architecture. That includes the Radeon HD 7700 series (Cape Verde Core), 7800 series (Pitcairn), and 7900 series (Tahiti), at the very least. AMD may include some 40 nm products under the 7000-series umbrella, and those would employ rebranded VLIW4/5 architectures.

The Southern Islands-based cards share the same features and abilities, which is good news. Here is a slide showing the placement of new product families relative to the Radeon HD 6000 series:

As you’ll see in our tests, the Radeon HD 7900 series appears to perform as its position in the deck would suggest. Note the Q1, 2012 expected date and the unnamed dual-GPU product at the top of the food chain.

With the relative performance of Radeon HD 7000-series cards established by AMD’s marketing department, let’s have a look at the family’s unique features. We’ll start with the basics: the Southern Islands architecture.

  • thepieguy
    If Santa is real, there will be one of these under my Christmas tree in a few more days.
    Reply
  • a4mula
    From a gaming standpoint I fail to see where this card finds a home. For 1920x1080 pretty much any card will work, meanwhile at Eyefinity resolutions it's obvious that a single gpu still isn't viable. Perhaps this will be something that people would consider over 2x 6950, but that isn't exactly an ideal setup either. While much of the article was over my head from a technical standpoint, I hope the 7 series addresses microstuttering in crossfire. If so than perhaps 2x 7950 (Assuming a 449$) becomes a viable alternative to 3x 6950 2GB. I was really hoping we'd see the 7970 in at 449, with the 7950 in at 349. Right now I'm failing to see the value in this card.
    Reply
  • mi1ez
    Damn, that's a good looking GPU!
    Reply
  • cangelini
    a4mulaFrom a gaming standpoint I fail to see where this card finds a home. For 1920x1080 pretty much any card will work, meanwhile at Eyefinity resolutions it's obvious that a single gpu still isn't viable. Perhaps this will be something that people would consider over 2x 6950, but that isn't exactly an ideal setup either. While much of the article was over my head from a technical standpoint, I hope the 7 series addresses microstuttering in crossfire. If so than perhaps 2x 7950 (Assuming a 449$) becomes a viable alternative to 3x 6950 2GB. I was really hoping we'd see the 7970 in at 449, with the 7950 in at 349. Right now I'm failing to see the value in this card.
    I'll be trolling Newegg for the next couple weeks on the off-chance they pop up before the 9th. A couple in CrossFire could be pretty phenomenal, but it remains to be seen if they maintain the 6900-series scalability.
    Reply
  • cangelini
    thepieguyIf Santa is real, there will be one of these under my Christmas tree in a few more days.
    Hate to break it to you, but there won't be, unless you celebrate Christmas in mid-January.

    Start treating your SO super-nice and ask for one for Valentine's Day!
    Reply
  • Darkerson
    Well I know what I want at tax time :D
    Reply
  • danraies
    cangeliniStart treating your SO super-nice and ask for one for Valentine's Day!
    If I ever find someone that will buy me a $500 graphics card for Valentine's Day I'll be proposing on the spot.
    Reply
  • a4mula
    cangeliniI'll be trolling Newegg for the next couple weeks on the off-chance they pop up before the 9th. A couple in CrossFire could be pretty phenomenal, but it remains to be seen if they maintain the 6900-series scalability.
    While I have little doubt that 2x of these cards would be very impressive, so would the $1100+ pricetag. I guess coming from the 580 SLI standpoint it might not seem like much, but if you've been considering the $750 ($900 for mobo+psu difference) 3x 6950 route like myself it seems like a major jump.

    Of course this is all just initial reaction towards the earliest of benchmarks. Given awhile to really dig around the new 7xxx, while allowing it to mature from a driver standpoint might make the 3x6950 seem foolhardy.
    Reply
  • Zombeeslayer143
    WOW!!! I love the conslusion; all of it, which basically is interpretted as "I'm biased towards Nvidia," and trys to say don't buy this card! Has the nerve to mention Kepler as an alternative; right, Kepler, as in 1 year away. The GTX580 just got "Radeon-ed" in it's rear. I'm not biased towards either manufacturer, just love to see and give credit to a team of people with passion, vision, and hardwork come together and put their company back on the map, as is shown here today with AMD's launch of the 7970. It's AMD's version of "Tebow Time!!"
    Reply
  • Zombeeslayer143
    No hard feelings to the author...thanks for the review nonethless..
    Reply